##### ###### ##### ### # # ### # # ###### ## ## ## ## ## ## ## # # # # # ## ##### #### ##### # # # # # # # #### ## # ## ## ## ## # # # # # ## ## # ###### ## ### # ### # ######
##### ###### ##### ### # # ### # # ###### ## ## ## ## ## ## ## # # # # # ## ##### #### ##### # # # # # # # #### ## # ## ## ## ## # # # # # ## ## # ###### ## ### # ### # ######
(Slope relationships)
Two lines are parallel if they have the same slope. Lines with slopes 2 and 2 are parallel.
Two lines are perpendicular if their slopes multiply to -1. A line with slope 2 is perpendicular to a line with slope -1/2, because 2 × (-1/2) = -1.
These relationships help determine right angles and shape properties.
